The root cause of Earth Warming is Ice Extent Retreat which decreases Albedo. The root cause of Ice Extent Retreat is a lack of snowfall to replace ice and snow that melts every year during the warm seasons. The root cause of a lack of snowfall is the cold and frozen water, in lakes and oceans, that fail to provide moisture for snowfall. The root cause of frozen water is a cold climate such as the Little Ice Age.
The root cause of Earth Cooling is Ice Extent Advance which increases Albedo. The root cause of Ice Extent Advance is an excess of snowfall necessary to replace ice and snow that melts every year during the warm seasons. The root cause of the excess of snowfall is the thawed lakes and oceans that do provide moisture for snowfall. The root cause of thawed lakes and oceans is a warm climate, such as now and the Medieval Warm Period and the Roman Warm Period.
The root cause of the tipping point between warming and cooling is the temperature that sea ice melts and freezes. Warming occurs because and after sea ice is frozen. Cooling occurs because and after sea ice is thawed. A large amount of the snow has already started to fall. Most of the cooling will occur some years later as it did after the Medieval Warm Period and after the Roman Warm Period.
Manmade CO2 has only a fraction of a trace of a chance to be a Root Cause of Major Warming, which, by the way, according the head of the IPCC has not happened for the past seventeen years.